Writing exams can be stressful. I learned early on that standing in a herd of people who are frantically asking each other questions or just generally stressing out, wasn’t good. So I got the answer—sit down the hall or on a nearby hill where I can see the lineup—but am not in it—who cares if I am last in? A second approach is to show up 2 minutes before the exam—this requires a bit of bravery but it is the ultimate in a relaxed start to an exam. Most people get there 20 min or 30 minutes before the exam and spend all that time around people who are sucking their energy away. Save it.
I pushed my theory to the ultimate test in my last year and went into an exam intentionally late so as to avoid any rush—however, this approach carries risks—not the least of which is getting into the exam. In my case, I got in and all was well—but the glare from the professor reminded me that it is not good to annoy the person marking your exam.